pgsql: Remove flaky isolation tests for timeouts

Remove flaky isolation tests for timeouts

51efe38cb92f introduced bunch of tests for idle_in_transaction_session_timeout,
transaction_timeout and statement_timeout. These tests were too flaky on some
slow buildfarm machines, so we plan to replace them with TAP tests using
injection points. This commit removes flaky tests.

Discussion: https://postgr.es/m/CAAhFRxiQsRs2Eq5kCo9nXE3HTugsAAJdSQSmxncivebAxdmBjQ%40mail.gmail.com
Author: Andrey Borodin

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a661bf7b0f56dd8bc298309de9937081ef485370

Modified Files
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src/test/isolation/expected/timeouts.out | 79 +-------------------------------
src/test/isolation/specs/timeouts.spec   | 40 +---------------
2 files changed, 2 insertions(+), 117 deletions(-)